1 | export = Semaphore;
|
2 |
|
3 |
|
4 | /** A simple abstraction for limiting concurrent function calls to a specific upper bound. */
|
5 | class Semaphore {
|
6 |
|
7 | static unlimited = new Semaphore(10000000);
|
8 |
|
9 | constructor(private n: number) {
|
10 | this._avail = n;
|
11 | }
|
12 |
|
13 | enter(fn: () => void) {
|
14 | if (this._avail > 0) {
|
15 | --this._avail;
|
16 | fn();
|
17 | } else {
|
18 | this._queued.push(fn);
|
19 | }
|
20 | }
|
21 |
|
22 | leave() {
|
23 | if (this._queued.length > 0) {
|
24 | var fn = this._queued.pop();
|
25 | fn();
|
26 | } else {
|
27 | ++this._avail;
|
28 | }
|
29 | }
|
30 |
|
31 | private _avail: number;
|
32 | private _queued: Function[] = [];
|
33 | }
|